In Cornwall, ruinous tin and copper mines are yielding battery-grade lithium. Here's what that means.

Cornish Lithium lead geologist Lucy Crane walks through a forest towards an old processing plant at United Downs. An area once dominated by copper and tin mines, the location – in Gwenapp, Cornwall – is the site of exploratory drilling for lithium, and also the Deep Geothermal Power Project, which aims to use heat from the earth as a domestic power source.  

Photograph by Jonny Pickup, National Geographic
By Dominic Bliss
photographs by Jonny Pickup
Published 28 May 2021, 11:47 BST

“IT MAY PROVE of great commercial value,” said chemistry professor William Allen Miller when, in 1864, he realised just how much lithium there was in the spring waters of Cornwall.

It was quite the understatement. At his laboratory at King’s College London, he had received a batch of stoppered bottles filled with water from “a remarkable hot spring” 230 fathoms (420 metres) beneath Wheal Clifford copper mine, near the town of Redruth. On analysis, he discovered they contained eight to 10 times more lithium than in any spring water known at that time. “The occurrence of so large an amount of lithium invests this water with unusual interest and importance,” he wrote in that year’s edition of The Chemical News and Journal of Physical Science. 

A century and a half later, thanks to the global demand for lithium batteries, Miller’s “great commercial value” is finally being realised. Right now, all over the world, manufacturers of batteries destined for electric vehicles, laptops and mobile phones are clamouring for more and more lithium. Might Cornwall soon become Europe’s ground zero for extraction of this soft metal?

That’s certainly what miner Jeremy Wrathall is banking on. Chief executive of mineral extraction company Cornish Lithium, which he set up in 2016, he’s convinced there’s a vast supply of this essential metal lying beneath the ground and coastal waters of Cornwall. And it’s all thanks to the granite.

Of rock and water

In Cornwall you’re never far away from granite. From Dartmoor in the east, to the Isles of Scilly in the west, enormous outcrops of the igneous rock poke up above the ground. Even greater amounts stretch deep underground and out to sea. Gritty and hard, it has been quarried for centuries so that you see it in Cornish houses, churches, bridges, pavements and monuments. (Read: do we know enough about the deep sea to mine it?)

Look closely at this granite and you’ll spot tiny black flecks in the rock called mica. It’s here, and in the geothermal waters washing through the subterranean rocks, that the lithium is found.

A worker walks beneath one of many industrial-spoil mountains – known locally as the Cornish Alps ...

A worker walks beneath one of many industrial-spoil mountains – known locally as the Cornish Alps – created through china clay mining two centuries ago. Cornish Lithium is currently running an exploratory campaign to map lithium density in the hard rock beneath the county.

Photograph by Jonny Pickup, National Geographic
Drilling for rock samples beneath Trelavour mine, St Dennis, Cornwall. The rock cores are examined for ...

Drilling for rock samples beneath Trelavour mine, St Dennis, Cornwall. The rock cores are examined for lithium density, in order to build a 3D picture of deposits beneath Cornwall that will inform future extraction. 

Photograph by Jonny Pickup, National Geographic
The ruins of Garland's engine shaft, overgrown and crumbling, at United Downs. Ruins like this were ...

The ruins of Garland's engine shaft, overgrown and crumbling, at United Downs. Ruins like this were the sites where lithium was first detected in the area – back before such applied usage and demand were commonplace.  

Photograph by Jonny Pickup, National Geographic

Cornish Lithium Ltd is based at Penryn, on a campus shared by the universities of Exeter and Falmouth. The company is conducting test drilling at sites at United Downs (near Redruth) and Trelavour (near St Austell). Once they start commercial production, possibly as early as 2024, Wrathall and his colleagues aim to produce vast amounts of lithium hydroxide. (In the mining world, lithium is usually extracted as lithium hydroxide or lithium carbonate, and often referred to as “lithium carbonate equivalent”.) Their business model is based on extracting at least 10,000 tons a year from hard rock at a disused china clay mine near St Austell, plus “an unquantifiable amount from possibly hundreds of boreholes” into the subterranean geothermal waters. (Related: Yellowstone's super-volcano could be an energy source. Should it be?)

New metal

Already, Wrathall has negotiated mineral rights to huge swathes of Cornwall – 600 square kms of dry land and 400 square kms of adjoining seabed. The concentration of lithium he has extracted so far is, he claims, “the highest we know of in geothermal waters worldwide” – as much as 260 parts per million. In lithium mining, that’s a very big deal indeed.

Left: At Trelavour, water is cleared from a borehole for rock core drilling (right). 

Photograph by Jonny Pickup, National Geographic

Wrathall isn’t the only lithium prospector in the Southwest: a rival company called British Lithium, headquartered in Roche, just 30 miles away, are equally bold, aiming for 21,000 tons a year by 2026. According to battery researchers The Faraday Institution, UK demand for lithium carbonate will exceed 70,000 tons by 2035. Together, Cornish Lithium and British Lithium could, in theory, supply the lot.

Why the lust for lithium, though? What does this metal have that makes it so crucial in battery production? Lucy Crane is senior geologist at Cornish Lithium. “It is the lightest weight metal, and it has a really high charge density,” she tells National Geographic UK. “In cars, laptops and mobile phones, you need batteries to be lightweight and portable. So lithium-based batteries are key. At the moment, all the battery mega-factories around the world are geared to lithium.”

A highly reactive metal, lithium doesn’t occur freely in the natural world. Although it’s widely distributed in the Earth’s crust and in seawater, it’s only in certain pegmatitic rocks (such as Cornwall’s granite), or in salt brines, that it’s found in a concentrated form. Even then, there are very few deposits where that concentration is high enough to merit commercial extraction. 

Drilled hard rock core samples that have been collected from Trelavour mine are cut, catalogued and analysed. The aim of the borehole drilling is to build a map of any potential lithium deposits beneath the surface. 

Photograph by Jonny Pickup, National Geographic

Whilst some of the borehole drilling speculating for lithium is on the spoil of old mines, much of it is small scale and incongruous, taking place at United Downs, on an industrial estate. The area was identified as a site to test for lithium-rich geothermal waters. The containers in the left of this image contain samples awaiting shipment to Vancouver for testing.

Photograph by Jonny Pickup, National Geographic

According to the US Geological Survey, the world’s largest lithium producer is Australia, extracting around 40,000 tons a year from hard rock spodumene deposits. Chile and Argentina source large amounts from brine pools in a region of the Andes called the Lithium Triangle. China is also a major producer and processor. 

Methods under the microscope

But as Cornish Lithium are keen to point out, the mining methods of these leading producers heavily impact the environment. “Hard rock mining entails drilling and blasting solid rock, before it is collected up, crushed and processed to extract the lithium-bearing minerals from the rest of the rock,” they explain on their website, adding that the extract is then roasted at temperatures up to 1,000 degrees centigrade. Brine pools, meanwhile, require lithium-enriched water to be pumped to the surface into evaporation ponds. “Solar evaporation techniques are highly inefficient, generate significant volumes of waste and use large amounts of scarce, highly valuable water,” they add, promising that their mining methods will have “minimum impact on the Cornish landscape”.

They’re planning two types of extraction: the first involves removing lithium from the granite rock without roasting it, although they can't reveal the precise method for intellectual property reasons; the second involves drilling boreholes – some down to two kilometres, others down to five kilometres – in the ground, before pumping up the geothermal waters to be processed at ground level. Crane says she has several partners trialling different technologies in a process known as direct lithium extraction, but has yet to decide which is most efficient.

“Tucked away in a field near an industrial estate, the deepest borehole drops down to 1100 metres, but with a hole diameter smaller than a dinner plate.”

To look at, the company’s boreholes near Redruth are distinctly underwhelming. Tucked away in a field near an industrial estate, the deepest drops down to 1100 metres, but with a hole diameter smaller than a dinner plate. Nearby is Wheal Clifford, the mine where William Allen Miller’s first samples of lithium-enriched spring waters were drawn to the surface. The crumbling wheelhouses and towers – relics of Cornwall’s 19th century tin and copper mining boom – still stand sentry over the shafts, which have since been closed off to stop hapless walkers stumbling into them.

Just to the north, at Wheal Maid, the countryside is still gouged and scarred where miners once worked the land. At the height of Cornwall’s copper extraction, the local parish of Gwennap was often described as “the richest square mile on Earth”.

There are sites like this dotted all over Cornwall, now abandoned to the elements. While ruinous today, they once provided many Cornish with a livelihood.

Wrathall hopes his lithium adventure will result in a 21st century mining boom; but this time, without the heavy environmental impact. “I want to do something for Cornwall,” he tells National Geographic UK. “Of course that sounds trite, but I really do passionately believe in an industry that could change this county in an ethical way.” A lithium rush, you might call it.

Top: an archivist prepares a map for digitisation at the University of Falmouth. Maps created during the Cornish mining boom of the 18th and 19th centuries such as the one pictured (bottom) are being analysed for insight and reference for drilling boreholes that will map potential lithium deposits. 

Photograph by Jonny Pickup / National Geographic (top); map image (bottom) courtesy Falmouth University

Old maps, new ambitions

Back at his headquarters in Penryn, Wrathall and his colleagues have amassed a vast archive of historical data in order to pinpoint the best locations for their boreholes. There are hundreds of old maps, mine plans, historical reports and cross-section drawings, dating back to Cornish mining’s golden age. There are dusty old geology PHDs and back issues of The Mining Journal. The company is currently digitising all this data – 25 terabytes of the stuff – combining it with satellite imagery to create 3D models of the Cornish landscape. “Including the large fault structures that are believed to host lithium in brine,” they explain.

Wrathall describes himself as a “mining geek”. “When I was seven years old, my parents would send me out to dig holes in the garden because I had too much energy,” he remembers. An interest in fossils and geology was fomented by his father who used to take him fossil hunting on the Dorset coast.

In the early 1980s he studied mining engineering at Camborne School of Mines, which is a stone’s throw away from Cornish Lithium’s headquarters in Penryn, and has recently supplied many of his employees.

After graduating, Wrathall spent time working in gold mines in South Africa. (“Underground every day, blasting, drilling; I was really thrown in the deep end.”) On returning to the UK he became a mining analyst, working for investment banks UBS and Deutsche Bank, eventually heading up the global mining team at financial company Investec. “I visited all sorts of mines all over the world and I always loved the engineering aspects of the industry,” he says.

Clockwise from top left: Geothermal water samples extracted from the United Downs borehole are refrigerated whilst awaiting examination. Lead geologist Lucy Crane explains the process of extracting lithium from geothermal waters. Behind her in green trays are hard rock borehole samples; crushed rock from drilled cores awaits examination; offsiders at the mine clear water from a flooded borehole before extracting rock samples.  

Photograph by Jonny Pickup, National Geographic

Then, in February 2016, he remembered how a colleague in the mining industry had told him about lithium deposits down in Cornwall’s old copper and tin mines. Knowing the demand for lithium batteries would escalate, he decided to leave his “very well paid job” and, five years ago, he set up Cornish Lithium.

Initially the venture was self-funded but now Wrathall has a war chest of £9.4 million in private investment, and £3.6 million in government funding. He suggests that, within five years, his company may be employing up to 400 people. There’s even a possibility he may get involved in the construction of a lithium battery factory in Cornwall.

There could be other valuable technology metals in this part of the Southwest. Copper and tin are a given, but Cornish Lithium know they have a chance of discovering “cobalt and other metals which are vital to the development of modern technologies such as batteries”. Wrathall adds: “Who knows what technology metals there could be? I can tell you for an absolute fact there is caesium here.” In spite of these lucrative by-products, he stresses that lithium still remains his primary focus. 

New mining ventures invariably court some sort of environmental opposition. Given the so-far light impact of this one, Wrathall insists that, so far, no one has obstructed his. (A brief online search uncovers no local opposition groups to his lithium extraction.) He has been quizzed over whether his methods will involve fracking, though. “The answer is absolutely not,” he counters. “The ground is already naturally fractured.”

Geologist Alan Baker examines hard rock borehole samples. In his hand is the first bag of battery-grade lithium the mine has produced. 

Photograph by Jonny Pickup, National Geographic

Wrathall also promises his methods will pose no danger to wildlife or drinking water. “We are regulated by the Environment Agency, by UK authorities, and by the Cornwall council,” he adds. “If there were risks, they wouldn’t give us planning permission.”

As regards the general environmental implications of the operation, much is still up in the air. Or, rather, under the ground. Critically it depends on whether the focus of Cornish Lithium – or anyone else – lies on extracting lithium from geothermal brines, or the hard rock. Each have their potential pitfalls, but as regards most criteria, one has rather fewer. 

“Relative to hard rock mining, extraction of a metal like lithium from brine I would anticipate there are environmental benefits,” says Paul Lusty, Critical Raw Material Topic Lead for the British Geological Survey. “Much of the discussion and emphasis of Cornish Lithium seems to be on its recovery from metal enriched fluids that naturally exist in the ground. But they’re also interested in the lithium content of mica, one of the main minerals in granite.  And they’ve been doing some work on what we term hard rock deposits. They are looking at what we term both types of resources. There’s two very separate approaches.”

Hard rock mining is, as mentioned, a world of holes in the ground, blasting, crushing. Regardless of the visual impact, it's highly energy intensive. Recovery from brine has many benefits, not least according to Lusty, that prospective developers “don’t have to dig an open pit, and can use directional drilling to access a resource from a point on the surface where there are no restrictions.”

This would typically involve at least two holes, and a circulation system of pumping up lithium-rich brine from a subsurface pool, directing it through a lithium extraction method, then – presumably – re-injecting it into the ground. Possible hazards in this method is that removing pockets of water from the ground can cause pressure changes, which can then cause seismicity – small earthquakes – along faults and fractures. But such hazards, Lusty says, are watched closely. 

“They can rarely be detected at the surface,” he says, but are “the reason why there is quite strict monitoring via a seismic network within the UK. Some of the developers also install more extensive seismic networks around project sites.” Such monitoring, he says, would be a regulatory requirement.

In addition, when it comes to lithium mining, as an approach, direct lithium extraction via brine pumping is exploratory territory in itself. “It’s not what you’d call conventional. It's a fairly new technique,” says Lusty. “There’s probably still some significant development required, depending on the chemistry of the brine.”   

Future proof?

A further worry is whether, in the future, battery technology might progress to use other elements instead of lithium. Hydrogen fuel cells and sodium batteries are both being developed, for example.

Wrathall stresses how lithium’s lighter weight and stronger charging density make it perfect for electric cars. “Go for your life if you want to find something better than that. There isn't anything.” And he points out how car manufacturers such as Tesla, VW and BMW have all fully committed to lithium. 

Despite concerns over the availability of other components, and the question of what to do with spent batteries, the global demand for lithium batteries is showing no signs of slowing. According to the International Energy Agency, the batteries of electric vehicles sold worldwide in 2019 required 17 kilotons of lithium. By 2030, this figure will rise to a staggering 180 kilotons a year.

The lion’s share of this will come from existing mines in Australia, China and South America. But, Wrathall hopes, Cornwall’s contribution won’t be insignificant. In any case, it's simply a question of how much is there, in what form.

According to Paul Lusty from the British Geological Survey, that picture is still being drawn – and even when it is, there will likely be a gap between establishing a resource, and making it industry-ready. “There’s a lot of interest in its mineral resource potential, but I think many of the companies exploring in Cornwall are still at a fairly early stage.” he says. “There’s still a number of questions about how much exists in the ground – either hard rock, or in the form of brines – until they publish a formal mineral resource assessment.”

For now, the fact that lithium is there at all is enough to energise efforts to find it. Back in 1864, in his King’s College London laboratory, William Allen Miller would never have suspected the lithium deposits he spotted in his water samples would one day be driving a global fleet of electric vehicles. Not in his wildest dreams.

Dominic Bliss is a freelance journalist based in London; follow him on Twitter. Jonny Pickup is a documentary photographer and film-maker. Follow him on Instagram.

Additional reporting by Simon Ingram


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